Process of concentrating ore by flotation



Patented Nov. 7, 1933 UNITED STATES PAT PROEESS 0F UONCENTRATINE @RE BYFLOTATION Frederick G. Moses, New York, Raymond w.

Hess, Buflalo, and Robert L.

Aurora, N. Y.,

Perkins, East assignors to The Barrett Company, New York, N. Y., acorporation oi New Jersey No Drawing. Application February 115, W27

Serial No. 168,465

12 Claims. (Cl. fillfilldfi) This invention relates to the separation ofminerals and the concentration of ores by flotation processes, and isparticularly directed to such separation and concentration carried outwith t the utilization of certain organic sulfur compounds as flotationagents.

According to the present invention, the separation of minerals and theconcentration of ores by the flotation operation is carried out with theaid J3 of a carbocyclic mercaptan or the aromatic series which containsno nitrogen in its composition. The invention enables improved resultsto be obtained, these being manifested sometimes in better recoveries,sometimes in producing a higher grade concentrate, sometimes in reducingthe time required for carrying out the flotation operation, andsometimes in efiecting the usual recoveries with a lesser quantity ofirothing agent than ordinarily required.

e The aromatic carbocyclic mercaptans or thicphenols employed as theflotation agents or adjuvants in the process of the present inventioncomprise those nitrogen-free mercaptans which cona mercapto group-SH,bound or attached to a carbon atom which is a component member of anaromatic carbocyclic ring or nucleus (a nuclear carbon atom). Theyinclude the nitrogen-tree inercaptans of the benzene, the naphthalene,the anthracene, and other aromatic carbocyclic series. Aromaticcarbocyclic mercap= tans or the benzene series are particularly irn=portant.

in general, the carbocyclic mercaptans or s thiophenols employed in thepresent invention may be prepared by reducing an aromatic sulionylchloride, or bythe action of an alkali hydrosulfide on salt of anaromatic sulionic acid, or hy the action of an alkali metal sulfide orsulihydrate, or salt of xanthic acid, on an aromatic diazo compound.Other suitable methods may be emyed. The pure or purified thiophenolbody is preferably employed.

In carrying out the flotation process, the data: agent comprising thenitrogen-free aromatic caloccyclic mercaptan body may be incorporatedwith the ore or the mineral pulp in any suit= able manner and at anysuitable time in accordance with customary known practices as wfll in-=sure a satisfactory flotation operation. For ex ample, it may beintroduced in the free state or as a salt into the mill in which the oreis being ground, or it may be dissolved, suspended or disersed in anysuitable solvent or dispersing agent as, for example, in one or more ofthe usual flotation oils or oil mixtures, or in water or in an. alkalior alkaline reagent, and incorporating the resulting suspension,solution or dispersion with the ore or the ore pulp. While the agents ofthe present invention show marked action as flotation agents in oreconcentration, they possess little, if any, frothing qualities andtherefore are used to advantage in conjunction with any suit= able orwell known irothing agent, e. g. pine, oil, crude turpentine, tar acids,etc. They may be also sometimes used to advantage in conjunction withother flotation agents.

The process or the present invention can be carried out in any suitableapparatus, for example, those oi the pneumatic type such as the callowcell, or those where the air is incorporated m with the mixture byagitation such as the Janney apparatus, or the like.

lit is of advantage in many cases, as with certain copper ores, tosubject the ore pulp to the action of an amount of alkali sufiicient togive it 5 a neutral or alkaline reaction before subjecting it toflotation with the aid of the flotation agents of the present invention.The alkali may be caustic alkali such as caustic soda, or an alkalinesalt such as soda ash, or it may be calcium oxide m or hymate.

The amount of flotation agent required to be used in the flotationprocess will vary, it depending partly on the character and compositionof the ore, partly on the particular carbocyclic 35 mercaptan employed,and partly on other fac tors. With many of these agents, one-fifth toone-half of a pound per ton of dry ore will be surdcient. Larger orsmaller amounts than this, however, can be used. w

The invention will be further illustrated by the following specificexamples, but it will be under== stood that the invention is not limitedthereto. The parts are by weight.

Erample 1.-soo parts of a copper sulfide ore 5 (of the InspirationConsolidated Copper Com= parry) assaying 1.49 percent copper was groundin a ball mill with 3&0 parts water and Q75 parts hydrated lime(equivalent'to 3 pounds hy drated lmoe per ton of ore) until practicallyall you of the mixture was sufiiciently fine to pass a all mesh screen.The ground pulp was diluted suidcient water added to give a pulpcontaining about it percent solids and subjected to flotation in aJanney flotation apparatus, with the addilob tion of a solutioncontaining 0.0625 parts of thicphenol (phenyl mercaptan) dissolved in anequivalent amount of normal caustic soda. After agitating for two orthree minutes, a small amount,

e, g. W92 to 0.04: parts of pine oil was added. A W1) satisfactorymineral froth was produced. Dur ing the next 25 minutes of agitation, anequal amount of pine oil was added or enough to make a total of about0.04 to 0.08 parts in all, i. 6., about one-sixth to one-third pound perton of ore. Mechanical agitation of the pulp was continued for about 5minutes after all of the pine oil had been added. 58 parts of aconcentrate assaying 11.65 percent copper was obtained. A recovery of92.3 percent of the copper was there-, fore obtained in the concentrate.The tailings assayed 0.13 percent copper. It will be noted that theequivalent of 8.45 tons of ore were required to give 1 ton ofconcentrate.

In a similar test when using 500 parts of another copper ore (of theMiami Copper Company) assaying 1.21 percent copper and the same amountof thiophenol, there was obtained 22 parts of concentrate assaying 21.1percent copper which is a recovery of 76.8 percent. The tailings assayed0.29 percent copper. In this test, the equivalent of 22.! tons of oregave 1 ton of concentrate.

Example 2.-500 parts of a copper sulfide ore (of the Miami CopperCompany) assaying 1.21 percent copper was treated as described inExample 1 except that 0.0625 parts para-thiocresol (equivalent toone-quarter pound per ton of ore) was used in place of 0.0625 parts ofthiophenol. 21.8 parts of concentrate assaying 21 percent copper wasobtained. This is a recovery in the concentrate of '75.? percent copper.The tailings assayed 0.31 percent copper. In this example the equivalentof 22.8 tons of ore gave 1 ton of concntrate.

In another test when using 500 parts of an ore (of the InspirationCopper Company) assaying 1.25 percent copper and 0.0625 gramspara-thiccresol, but otherwise treated as in Example 1,

there was obtained 47.7 parts of concentrate assaying 12.47 percentcopper which is a recovery of 88 percent. The tailings assayed 0.18percent copper. In this test, the equivalent of 10.5 tons of ore gave 1ton of concentrate.

Example 3.--500 parts of a copper sulfide ore (of the Miami CopperCompany) assaying 1.25 percent copper was treated as described inExample 1 except that 0.0625 parts beta-thionaphthol(2-mercapto-naphthalene) was used in place of 0.0625 parts ofthiophenol. 20.8 parts of concentrate assaying 22.2 percent copper wasobtained which is a recovery of 74.1 percent. The tailings assayed 0.34percent copper. In this example, the equivalent of 23.3 tons ore gave 1ton of concentrate.

Example 4.500 parts of ore (of the Inspiration Copper Company) assaying1.47 percent copper was treated as described in Example 1 except that0.0625 parts of 2-mercapto-anthraquinone was used in place of the 0.0625parts thiophenol. 51 parts of concentrate assaying 9.9

percent copper was obtained. This is a recovery of 71.5 percent. In thisexample, the equivalent of 9.45 tons of oregave 1 ton concentrate. Theconcentrates obtained in the above examples were so-called roughconcentrates, that is, they were concentrates which were not cleaned byretreatment or re-flotation.

In carrying out the process, the flotation agent can be used in the dryform, if desired; or it can be added to and ground with the ore. It mayalso be used in conjunction with other frothing agents or with otherflotation agents, or with both. In general, it is preferably employed insolution in caustic alkali but its salts, particularly the sodium,potassium or ammonia salts, or salts of organic bases, may also beemployed.

It will thus be seen that the present invention utilizes as flotationagents in the separation of minerals and the concentration of ores thenitrogen-free aromatic carbocyclic mercaptan bodies, substances orcompounds; that said flotation agents may be incorporated in or with theore in any suitable or well-known manner; that they may be used inconjunction with other flotation agents or with frothing agents or withboth; and that they may be added in the dry state in the free conditionor as salts, or in solution, suspension or dispersion in any suitablesolvent or medium.

The present invention is of more or less general application to thetreatment of various kinds of mineral mixtures, both natural andartificial, which are amenable to concentration by flotation processes.

It will be further understood that the invention is not limited to theuse of the particular agents or ingredients mentioned as examples andthat other agents of the class mentioned can be used.

In the claims, it will be understood that the expression nitrogen-freearomatic carbocyclic mercaptan containing not more than fourteenR-carbon atoms in the carbocyclic nucleus comprehends the nitrogen-freemercaptans of the benzene series (which has six R-carbon atoms), of thenaphthalene series (which has ten R-carbon atoms), and the anthraceneseries (which has fourteen R-carbon atoms). It will be furtherunderstood that the expression hydroxyl group signifies and includes thehydroxyl group as well as groups or radicals which contain a hydroxylgroup, 6. g., OH, SOzOH, COOH, etc.

We claim:

1. In effecting the concentration of minerals, the process whichcomprises mixing with the mineral pulp a flotation agent in which thereis predominantly present a nitrogen-free aromatic carbocyclic mercaptanbody, and subjecting the resulting mixture to a froth flotationoperation.

2. In effecting the concentration of minerals, the process whichcomprises subjecting the mineral pulp to a froth flotation operation inthe presence of a flotation agent in which there is predominantlypresent a nitrogen-free thiophenol body of the benzene series.

3. In effecting the concentration of minerals the process whichcomprises subjecting the mineral pulp to a froth flotation operation inthe f carbocyclic mercaptan embodying within its composition thefollowing atomic grouping:

o-sn c 5. In effecting the concentration of minerals,

the process which comprises incorporating with a mineral pulp aflotation agent consisting essentially of a nitrogen-free aromaticcarbocyclic mercaptan containing not more than fourteen R-carbon atomsin the carbocyclic nucleus, and.

subjecting the resulting mixture to a froth flotation operation.

6. In effecting the concentration of minerals, the process whichcomprises incorporating with a mineral pulp a flotation agent consistingessentially of a nitrogen-free aromatic carbocyclic mercaptan containingnot more than ten R-carbon atoms in the carbocyclic nucleus, andsubjecting the resulting mixture to a froth flotation operation.

7. In efiecting the concentration of minerals, the process whichcomprises incorporating with a mineral pulp a flotation agent consistingessentially of a nitrogen-free aromatic carbocyclic mercaptan containingnot more than six R-carbon atoms in the carbocyclic nucleus, andsubjecting the resulting mixture to a froth flotation operation.

8. In effecting the concentration of minerals, the process whichcomprises mixing with the mineral pulp a nitrogen-free aromaticcarbocyclic mercaptan, having in its composition a double bond adjacentto the grouping CSH, in the proportions of about one-fifth to aboutone-half pound of mercaptan per ton of dry mineral, and subjecting theresulting mixture to a froth flotation operation.

9. In efiecting the concentration of minerals, the process whichcomprises mixing with the mineral pulp a flotation agent consistingessentially of an aromatic carbocyclic mercaptan which, besides themercapto group, contains only carbon and hydrogen in its composition,and in which the mercapto group is attached to a nuclear carbon atom,and subjecting the resulting mixture to a froth flotation operation. 7

10. In effecting the concentration of minerals, the process whichcomprises mixing with the mineral pulp an aromatic carbocyclic mercaptanof the benzene series which, besides the mercapto group, contains onlycarbon and hydrogen in its composition, and in which the mercapto groupis attached to a nuclear carbon atom, in the proportions of aboutone-fifth to about one-half pound of mercaptan per ton of dry mineral,and subjecting the resulting mixture to a froth flotation operation.

11. In effecting the concentration of copper sulfide ores, the processwhich comprises mixing with a pulp of the ore a flotation agentconsisting essentially of phenyl mercaptan, and subjecting the resultingmixture to a frothfiotation operation.

12. In efl'ecting the concentration of copper sulfide ores, the processwhich comprises mixing with a pulp of the ore a flotation agentconsisting essentially of para-thiocresol, and subjecting the resultingmixture to a froth flotation operation.

FREDERICK G. MOSES. RAYMOND W. HESS. ROBERT L. PERKINS.

